Ancient Egyptians paid special attention to the organs of their dead, embalming them so they would continue to function in the afterlife. Now it seems they did the same for sacrificed ibis birds, and even packed their stomachs with food so they wouldn't go hungry.

Ibis mummies are found in their millions at shrines in Egypt, where they were sacrificed to Thoth, the god of writing and wisdom. Andrew Wade at the University of Western Ontario in London, Canada, and his colleagues used a CT scanner to look inside two mummified adult ibises and one hatchling. This revealed that embalmers had removed their internal organs. The adult gizzards, complete with snail shells which may have come from the birds' last meals, were then replaced. The hatchling's body cavity had been stuffed with grain.

Studies of human mummies show that ancient Egyptians often removed and embalmed the lungs and digestion organs before placing them back inside the body – perhaps so they might work in the afterlife. The ibis mummies suggest Egyptians believed that birds also travelled to the afterlife, says Wade. "It suggests the provision of an afterlife food source to the bird," he says, "and lends support to the idea that the viscera of ibises and humans alike were meant to continue their living function within the afterlife."